Italy's Bizarre double-boiler steam trains - "Franco-Crosti" Boilers

Over the years, many people have tried many different ways to make

steam

locomotives more efficient, from using different fuels to different body shapes and

boiler

types. In Italy, designers thought they could improve

steam

locomotives by simply adding another

boiler

that surprisingly worked like steam locomotives. The running water in the boiler is heated and converted into steam which then flows into its cylinders to create motion before being used up because the used steam is used up over time, the water in the boiler will be used up, so the boiler equipment footrest must continue to be filled with transported water. in the engine or Tender tanks, the problem is that this water is usually cold and as a result, when injected into the boiler, the cold water decreases the temperature in the rest of the boiler, reducing the boiler pressure, which in turn negatively affects engine performance.

The engine then needs to burn more fuel to bring the now colder boiler back up to temperature in an ideal world. You want the water you are putting in the boiler to be as hot as possible to decrease the amount of energy needed to boil. It is a problem that many engineers have tried to address since the early days of steam and has led to many unique feedwater heater designs. Some simply involve heating the pipe through which the water is injected, while others involve venting steam from the boiler into the engine water. tanks for many Italian railways, however this was not enough, unlike Britain or Germany, Italy had to import most of the coal it needed to operate its railways, usually at high cost and as such many railways Italians wanted to reduce the amount of coal their locomotives consumed.

To save money in the early 1910s, Atio Franco designed the Franco boiler, a system designed to preheat the feed water of locomotives using their exhaust gases instead of being expelled through the locomotive's funnel. Steam and gas from the combustion chamber would flow through what was essentially an additional boiler. boiler, this would heat the feed water before injecting it into the main boiler using the exhaust gases to preheat the water, ensuring that as little energy as possible was wasted and helping the engine get the most out of its fuel. However, Franco's design was not like that. It was used until 1932 for the Belgian-built quadruple locomotive.

It was equipped with two Franco preheaters mounted in front of the main locomotive. I spoilers Italy did not begin experimenting with Franco's design until 1937, when a class 670 cab-forward locomotive was modified and fitted with a preheater in its tender. After several tests, the engine showed a fuel saving of around 20%. % compared to the rest of the class, although the engine was discarded once testing concluded around this time, Atio Franco passed away and development of the design was taken over. Crosy advanced the design in 1939 by modifying five FS class 685 engines by adding two smaller preheaters that would be placed on either side of the locomotive's aileron instead of one large one. at the front, giving them the unique appearance of having three smoke boxes and exhausts mounted on both sides in the middle of the boiler, these were classed as 683s with special aerodynamic casings and were tested in various passenger services as the 670 before to them, the Streamline boxes were delivered.

For aesthetic purposes, only the cross-shifts prove successful: the 683 is proving to be 18.9% more fuel efficient compared to its 685-class counterparts, although it's worth noting that the 683 also has a design improved boiler compared to the 685, so not all. of its success and efficiency can be attributed to the Franco Crossy system and the Italian State Railways, seeing the improvements in fuel consumption, built 94 new locomotives using the Franco Crossy system in 1940, classified as 743, followed by several other modified classes. and equipped with new

boilers

both during and after World War II, as Franco Crossy

boilers

were favored in Italy, it was not long before other railways in Europe were also experimenting with the system.

In 1948, a 280 engine in Spain was modified as an IED and fitted with a Franco Crossy. boiler unlike its Italian counterparts, however, was equipped with a single preheater which was mounted below the boiler, what is even more unusual is that its exhaust supposedly traveled through the center of the engine boiler, why placed in such impractical places. Beyond me, West Germany followed suit by equipping two Class 52s with preheaters also under their boilers in 1951. By 1958, Germany had installed feedwater heaters on 31 Class 50 locomotives and the engines showed general improvement in terms of fuel efficiency. Oliver Bullyed also fitted an Irish locomotive with Franco Crossy heaters in 1951.

As part of his experimentation while developing Turf combustion locomotives for Ireland, although the end result performed poorly, 10 of British Railways' 9f locomotives were fitted with boilers. Franco Crossy, although quite unusually compared to other designs, still used the original engine funnel as well as the heater exhaust. which was mounted on the right side of the boiler, its ordinary funnel would be used while the engine was started or if more airflow was needed while running, but when not in use it would close. The 9fs were already some of the best steam engines in the world. Britain and while the Franco Crossy heaters provided a slight increase in performance, it was not enough to justify fitting more engines with them, especially considering how complicated they were to maintain, which brings us to some of the drawbacks of the Franco Crossy boiler and The reason all railroads did not install them immediately was, first of all, their weight, since feedwater heaters were usually mounted on the wheels of most of the engines on which they were installed, they greatly increased the loading width of the engine, meaning that some engines would end up too heavy to run on their intended lines, some railways solved this problem by mounting the heaters under the engine boilers and, while this helped with the weight distribution, meant that the engines boiled and the cabin would have to be raised to compensate, often causing problems. with the overall height of the engine, placing it in front of an engine, Smoke Box, like previous designs, would help with both weight and height, but at the cost of lengthening the engine, second was maintenance, many Franco designs Crossy suffered corrosion due to acid flu buildup. gases in the feedwater heater, meaning parts had to be replaced frequently to keep them running, this combined with the added hassle of cleaning.

What was essentially another boiler only added to response times and maintenance costs. It is also worth noting that some engines fitted with these water heaters also had to be fitted with smaller boilers to help accommodate them, as a result some engines such as the 9fs ended up being less powerful than their unmodified counterparts. Most railroad engineers took note of this and instead just focused on making locomotive spoilers more efficient. of adding these preheaters and finally the main reason why the Franco Crossy system didn't really take off outside of Italy was because high quality coal wasn't so scarce in the rest of Europe, as I said before.

Italy had to import most of its coal and because of how expensive it was, railways were keen to reduce the amount of fuel their engines burned to save money, while in countries like Germany and Britain high quality coal was an abundant resource and as such the installation and maintenance of Franor Crossy boilers would likely end up being more expensive than simply paying the difference for coal. In short all the benefits and fuel savings of Franco Crossy boilers provided they were held back by their excessive weight, excessive maintenance and the fact that similar results could be obtained with other more conventional diets. water heaters and a better designed boiler The fact that only a relatively small number of Italian locomotives were fitted with Franco crossy boilers despite their success shows that they were not always an automatic upgrade for each engine;

However, the engines that were improved went on to have a full working life, some functioning until the 1980s and a handful of them achieving conservation, the Franco Crossy boilers, although they were not as important an improvement as they seemed on paper, They proved to be a boon to Italian railways, even if many other countries did not use them as much. Subscribe for more.